1. Field of the Invention
The present invention relates generally to the field of torque-actuated tool apparatus, and more particularly, but not by way of limitation, to a tool assembly for transferring torque from a drive member to a driven member via a male element engaging with a mating female element.
2. Prior Art
A typical torque-actuated tool apparatus generally comprises a drive member such as, for example, a screw driver or wrench which is engaged to an object such as a screw, bolt, rotary valve or the like for driving or rotating the object via a torque applied to the drive member and transferred therefrom to the object, or driven member. More particularly, a torque transfer assembly usually includes one portion connected to the drive member and a mating portion connected to the driven member and is constructed to transfer the torque from the drive member to the driven member via an interface formed between the mating portions.
The mating portions of a torque transfer assembly may be more clearly defined as a male portion and a female portion which is sized and shaped to receive and, thus, engage or mate with the male portion. The general appropriateness of this analogy can be seen when considering the following: a screwdriver bit (the male portion) fits into one or more slots (the female portion) formed on the head of a bolt or screw; a socket (the female portion) slips over a bolt head (the male portion); and an Allen wrench (the male portion) is inserted into a mating socket (the female portion) of an Allen head screw or bolt.
Male portions such as those discussed above can be further characterized as having one or more projections, blades, ribs or the like extending from a central element such as a bolt, rod, or shank, for example. Correspondingly, a mating female portion will usually have a socket or opening formed therein having properly sized and positioned slots or recesses for receiving said projections, with inwardly extending faces or projections which contact and bear against the adjacent projections or male portions. Thus, a torque applied to the drive member about an axis aligned with the respective male or female portion will be transferred to the other of said portions via the contact or interface established therebetween.
The efficiency of the torque transfer is directly related to the area of surface contact between the male and female portions, as well as the direction in which the torque is transferred therebetween in relation to the direction that the torque is applied. For example, the torque is transferred relatively efficiently when the contacting surfaces are in planer contact and are aligned as closely as possible with the axis of the torque such that the torque is transferred therebetween in a direction perpendicular to said surfaces; as opposed to the surfaces being in point or line contact (which would create undesired stress forces) or being misaligned with said axis such that the torque is oblique to the surfaces. If the contacting surfaces are not aligned properly there is the likelihood that the male and female portions will slip apart or, at least, slip sufficiently to cause an undesired rounding off of the projecting elements.
Tool assemblies like those described above have been utilized in the past to effectuate such operations as radiator valve adjustment and attachment and detachment of threaded fasteners, for example. Through the years, these tool assemblies and related apparatus have often been specifically designed and constructed for particular, and sometimes limited, uses. For example, several wrench devices exist for use particularly with steam radiator valves. These tools are generally known as spud wrenches--a name derived from the spud, or ground nipple, commonly found on steam radiator heating units used during the early part of the twentieth century. Exemplary models of spud wrenches are disclosed in the U.S. Pat. Nos. 1,155,960, issued to Ruth, and 1,608,620, issued to Robinson. A typical spud wrench tool usually includes one or more common sizes of cylindric nipple engaging members, or wrenches, with two longitudinal grooves or recesses formed on each wrench for receiving the lugs of the spud or nipple on the radiator. The different sized wrenches are usually positioned in a stepped manner (shown in Ruth) or at opposite ends of a common rod (shown in Robinson) for servicing a variety of different sized spud valves.
Another wrench used for turning radiator valves, but not of the spud wrench type, is disclosed in the U.S. Pat. No. 961,515, issued to Montgomery. This tool has a plurality of axially aligned blades which are also positioned in a stepped relation to facilitate use thereof with a range of sizes of radiator valves. Montgomery's wrench is also disclosed as being useful as a pipe reamer.
The common "Phillips" screwdriver, and modified counterparts thereof, are also considered as being relevant to the present field of tools. These driving tools primarily comprise a shank having four tapered ribs or wings arranged at one end thereof for insertion into a mating socket of a Phillips head screw, or the like. Two examples of the Phillips type screwdriver are disclosed in the U.S. Pat. Nos. 2,601,453, issued to Phipard, Jr., and 3,616,327, issued to Stillwagon, Jr. The driving tool shown in Phipard, Jr. has an elaborately designed and fluted driving end constructed to provide a perpendicular driving thrust and, thus, prevent the driving tool from being forced out of the socket of a fastener or driven element. The Stillwagon, Jr. patent relates more particularly to a screwdriver bit having a non-magnetic, elastomeric coating formed thereon for retaining a screw type fastener on the end of the bit prior to driving. However, the screwdriver bits shown therein are basically similar in design and construction to those shown in the Phipard, Jr. patent.
Another driving tool which is somewhat similar to the Phillips screwdriver is the gear chuck key such as that shown in the U.S. Pat. No. 3,977,686, issued to Buck. The essence of this patent deals with apparatus for providing a self ejecting chuck key which otherwise appears to be of conventional design and construction.
One other pertinent apparatus is disclosed in the U.S. Pat. No. 1,753,154, issued to Martus, wherein a first headless set screw is used to lock a shaft, or the like, in place, and a similar second set screw is utilized to lock the first set screw in place. More particularly, each set screw has an axial opening formed therein for receiving a wrench tool, with one or more longitudinal slots formed through the set screw for receiving ribs formed radially on the wrench.